单项选择题
A.103%B.108%C.110%D.112%
A.3250B.3150C.3300D.3240
A.增加电网的频率B.减小电网的频率C.恢复电网的频率D.稳定电网的频率
A.1%B.2%C.3%D.0.3%
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